1;Check 5.5 Parameter Passing --> Stage C --> C.4 statement, when NSAA is not 2;equal to SP. 3; 4; Our purpose: make NSAA != SP, and only after start to use GPRs. 5; 6;Co-Processor register candidates may be either in VFP or in stack, so after 7;all VFP are allocated, stack is used. We can use stack without GPR allocation 8;in that case, passing 9 f64 params, for example. 9;First eight params goes to d0-d7, ninth one goes to the stack. 10;Now, as 10th parameter, we pass i32, and it must go to R0. 11; 12;5.5 Parameter Passing, Stage C: 13; 14;C.2.cp If the argument is a CPRC then any co-processor registers in that class 15;that are unallocated are marked as unavailable. The NSAA is adjusted upwards 16;until it is correctly aligned for the argument and the argument is copied to 17;the memory at the adjusted NSAA. The NSAA is further incremented by the size 18;of the argument. The argument has now been allocated. 19;... 20;C.4 If the size in words of the argument is not more than r4 minus NCRN, the 21;argument is copied into core registers, starting at the NCRN. The NCRN is 22;incremented by the number of registers used. Successive registers hold the 23;parts of the argument they would hold if its value were loaded into those 24;registers from memory using an LDM instruction. The argument has now been 25;allocated. 26; 27;What is actually checked here: 28;Here we check that i32 param goes to r0. 29; 30;Current test-case was produced with command: 31;arm-linux-gnueabihf-clang -mcpu=cortex-a9 params-to-GPR.c -S -O1 -emit-llvm 32; 33;// params-to-GRP.c: 34; 35;void fooUseI32(unsigned); 36; 37;void foo(long double p0, 38; long double p1, 39; long double p2, 40; long double p3, 41; long double p4, 42; long double p5, 43; long double p6, 44; long double p7, 45; long double p8, 46; unsigned p9) { 47; fooUseI32(p9); 48;} 49; 50;void doFoo() { 51; foo( 1,2,3,4,5,6,7,8,9, 43 ); 52;} 53 54;RUN: llc -mtriple=thumbv7-linux-gnueabihf -float-abi=hard < %s | FileCheck %s 55; 56;CHECK-LABEL: foo: 57;CHECK-NOT: mov r0 58;CHECK-NOT: ldr r0 59;CHECK: bl fooUseI32 60;CHECK-LABEL: doFoo: 61;CHECK: movs r0, #43 62;CHECK: bl foo 63 64define void @foo(double %p0, ; --> D0 65 double %p1, ; --> D1 66 double %p2, ; --> D2 67 double %p3, ; --> D3 68 double %p4, ; --> D4 69 double %p5, ; --> D5 70 double %p6, ; --> D6 71 double %p7, ; --> D7 72 double %p8, ; --> Stack 73 i32 %p9) #0 { ; --> R0, not Stack+8 74entry: 75 call void @fooUseI32(i32 %p9) 76 ret void 77} 78 79declare void @fooUseI32(i32) 80 81define void @doFoo() { 82entry: 83 tail call void @foo(double 23.0, ; --> D0 84 double 23.1, ; --> D1 85 double 23.2, ; --> D2 86 double 23.3, ; --> D3 87 double 23.4, ; --> D4 88 double 23.5, ; --> D5 89 double 23.6, ; --> D6 90 double 23.7, ; --> D7 91 double 23.8, ; --> Stack 92 i32 43) ; --> R0, not Stack+8 93 ret void 94} 95 96